/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;

import java.io.Serializable;
import java.util.Arrays;
import java.util.Comparator;
import javax.annotation.CheckForNull;

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An ordering that tries several comparators in order.
 */
@GwtCompatible(serializable = true)
@ElementTypesAreNonnullByDefault
final class CompoundOrdering<T extends @Nullable Object> extends Ordering<T>
        implements Serializable
{
    final Comparator<? super T>[] comparators;

    CompoundOrdering(Comparator<? super T> primary, Comparator<? super T> secondary)
    {
        this.comparators = (Comparator<? super T>[]) new Comparator[]{primary, secondary};
    }

    CompoundOrdering(Iterable<? extends Comparator<? super T>> comparators)
    {
        this.comparators = Iterables.toArray(comparators, new Comparator[0]);
    }

    @Override
    public int compare(@ParametricNullness T left, @ParametricNullness T right)
    {
        for (int i = 0; i < comparators.length; i++)
        {
            int result = comparators[i].compare(left, right);
            if (result != 0)
            {
                return result;
            }
        }
        return 0;
    }

    @Override
    public boolean equals(@CheckForNull Object object)
    {
        if (object == this)
        {
            return true;
        }
        if (object instanceof CompoundOrdering)
        {
            CompoundOrdering<?> that = (CompoundOrdering<?>) object;
            return Arrays.equals(this.comparators, that.comparators);
        }
        return false;
    }

    @Override
    public int hashCode()
    {
        return Arrays.hashCode(comparators);
    }

    @Override
    public String toString()
    {
        return "Ordering.compound(" + Arrays.toString(comparators) + ")";
    }

    private static final long serialVersionUID = 0;
}
